Today is celebrated as the birth of passenger railways with the opening of the Liverpool and Manchester Railway on 15th September 1830. Except that it's not: The Stockton & Darlington Railway had been running for the previous 5 years. But it is true that the opening of the L&M in the presence of the Prime Minister (the Duke of Wellington) and the Home Secretary (Sir Robert Peel) and many more of the Great and the Good, did make it an event worth reporting. That publicity certainly helped the flotation and the L&M was financially successful from the get-go. The publicity also went ballistic because of a concurrent tragedy.
George Stephenson had designed the railway with 4 parallel rails equidistant from each other and 4 ft 8.5in (1,435 mm) apart. I'll have to dig down another level to work out why that distance was chosen and not, say, 5ft even or 1.5m. But the 4 track design was chosen partly for redundancy: trains could run on the middle pair if the outer rails were broken or being repaired. But with the lateral overhang of each carriage above the wheels, there was only 20cm spare between trains. William Huskisson, the local MP and a rising star in Tory politics got caught between two trains while talking to the Duke and died after he was run over. He thus became the first casualty of the Railway Age, except that he wasn't: that honour goes to a blind American beggar-woman knocked down by a locomotive on the S&DR in 1827. But as Wikipedia has it, Huskisson was "the first railway fatality to be widely reported".
While we are on transport firsts everbode kno that Rosa Parks was the first black woman arrested for refusing to give up her bus-seat for a white man. Except that she wasn't: that honour goes to Claudette Colvin a 15 year old young-wan who had been arrested for the same 'crime' earlier in 1955. But between arrest and trial, she fell (ooops pregnant-while-unmarried) and was dropped like a red-hot brick as a fulcrum for leveraging civil rights by the respectable NAACP black community. It was much better politics to mobilise support for a poor middle aged seamstress. Colvin's boy was born in 1956 sufficiently light-skinned that, without anyone looking at the facts of the matter, she had the sin of miscegenation added to unmarried sex and sitting down in the wrong part of a bus. At the time it was hard to decide which of these offenses was most serious. Read all about it in the Grauniad. And thanks to QI talk for the pointer.